rations. Differences in lamb and beef cattle responses to high sulfur (S) diets require additional .... infection after conclusion of the gas sampling procedure. Table 1 ... characteristics were collected by trained personnel 24 hours after slaughter.
Interaction of corn processing and distillers dried grains with solubles on health and performance of steers B. W. Neville1, G. P. Lardy1, K. K. Karges2, S. R. Eckerman1,3, P. T. Berg1, and C. S. Schauer3 1 NDSU Department of Animal Sciences 2 Dakota Gold Research Association 3 NDSU Hettinger Research Extension Center Introduction One challenge with using ethanol co-products is the potential for sulfur-induced polioencephalomalacia (PEM) in ruminants (Gould, 1998). Research has demonstrated that lambs fed diets containing 60 percent dried distillers grains with solubles (DDGS) did not develop PEM (Neville et al., 2010) and performed similar to those fed lesser concentrations of DDGS (Schauer et al., 2008). Schauer et al. (2008) and Neville et al. (2010) provide evidence that use of DDGS can be increased in lamb finishing rations. Differences in lamb and beef cattle responses to high sulfur (S) diets require additional research. Average utilization of DDGS in the beef feedlot industry is 16.5 percent (Vasconcelos and Galyean, 2007); this is lower than the 20-30 percent inclusion rate suggested to optimize ADG and G:F (Klopfenstein et al., 2008). The reason for the low DDGS inclusion rate in beef feedlot diets could be economic or, more likely, a result of negative connotations with feeding co-products (i.e. sulfur content). Feeding 60 percent DDGS results in exceeding the maximum tolerable level of dietary S (0.3%; NRC, 2005). Neville et al. (2010) demonstrated that lambs can be fed a greater S concentration than recommended by NRC (2005). Our hypothesis was that feeding combinations of DDGS and either dry-rolled corn (DRC) or high-moisture corn (HMC) with dietary S content exceeding 0.3 percent S will not result in incidence of PEM. We further hypothesized that feeding high-moisture corn in combination with DDGS will increase ruminal hydrogen sulfide (H2S) gas concentrations over those found when feeding DDGS with dry-rolled corn. Admittedly, animal performance may suffer due to decreased palatability and intake as the concentration of DDGS increases. However, the economic benefit from decreased feed costs may warrant such feeding practices. The objective of this study was to evaluate the influence of feeding increasing concentrations of DDGS and corn processing method (high-moisture vs. dry-rolled corn) on animal performance, incidence of PEM, and concentration of ruminal H2S in feedlot steers. Materials and Methods All animal care and handling procedures were approved by the North Dakota State University Institutional Animal Care and Use Committee prior to the initiation of the research. Seventy-two mixed breed steer calves (750 ± 27 lbs) were utilized in a completely random design with a 3 x 2 factorial arrangement of treatments to evaluate the outlined objective. Animals were assigned to treatment at the time of arrival. Main effects included concentration of DDGS (20, 40, or 60% DM basis) and corn processing method [high-moisture (HMC) vs. dry-rolled corn (DRC)] resulting in treatments of (1) 20 percent DDGS with DRC, (2) 40 percent DDGS with DRC, (3) 60 percent DDGS with DRC, (4) 20 percent DDGS with HMC, (5) 40 percent DDGS with HMC, and (6) 60 percent DDGS with HMC. Treatment diets were formulated to meet or exceed dietary nutrient requirements for steers weighing 715 pounds and gaining 3.2 pounds daily (NRC, 2000; Table 1). The dietary treatments were formulated to have minimum Ca to P ratio of 1:1. Diets were formulated to provide 150 mg/hd/d thiamin based on an estimated DMI of 22 pounds; actual thiamin provided was 135.5 mg/hd/d. Prior to initiation of this study steers were vaccinated for clostridial and respiratory diseases and dewormed.
Table 1. Ingredient and nutritional composition of final finishing diets fed to steers.
Item Ingredient % Alfalfa Hay Corn Silage Corn1 DDGS2 CSB3 Supplement4
20% DDGS
Dry-rolled Corn 40% DDGS
60% DDGS
20% DDGS
5.0 10.0 58.2 20.0 5.0 1.8
5.0 10.0 38.2 40.0 5.0 1.8
5.0 10.0 18.2 60.0 5.0 1.8
5.0 10.0 58.2 20.0 5.0 1.8
High-moisture Corn 40% 60% DDGS DDGS
5.0 10.0 38.2 40.0 5.0 1.8
5.0 10.0 18.2 60.0 5.0 1.8
Nutrient composition % (analyzed) CP 15.9 20.8 22.6 16.1 19.6 23.0 NDF 25.5 30.1 31.7 24.6 27.6 30.9 ADF 7.7 8.8 8.6 7.8 8.5 8.5 Ca 1.1 0.9 0.7 0.9 0.9 0.7 P 0.6 0.7 0.9 0.5 0.7 0.8 S 0.6 0.7 0.9 0.6 0.7 0.9 Cu 0.003 0.003 0.002 0.003 0.003 0.003 Zn 0.01 0.1 0.1 0.1 0.1 0.1 1 Corn fed either as dry-rolled corn or high-moisture corn. 2 DDGS = distillers dried grains plus solubles. 3 CSB = concentrated separator byproduct. 4 Supplement contained (%, total ration, DM basis): limestone 1.7%; vitamin A, D, and E premix 0.02% [Trouw Nutrition, Highland, IL (1,500,000 IU vitamin A, 500,000 IU vitamin D, and 500 IU vitamin E)]; Rumensin 0.02% (176 g/kg monensin, Elanco Animal Health, Indianapolis, IN); Trace mineral premix 0.05% [Hubbard Feeds Inc., Mankato, MN (3.95% Ca, 2.56% Cu, 16.0% Zn, 4.0% Mn, 1,050 mg/kg I, and 250 mg/kg Co)]; 0.002% thiamin (analyzed concentration 13.55 mg/kg dietary DM). Steers were trained to use the Calan Broadbent Feeding System (American Calan, Northwood, NH) prior to adaptation to finishing diets. During this training phase steers were fed a diet consisting of 50 percent corn silage, 25 percent alfalfa hay, 25 percent dry-rolled corn (DM basis). Steers were maintained on this diet until day 0 at which time adaptation to final finishing diets began. Neither the receiving diet nor the training diet contained DDGS. Ruminal H2S gas concentrations were measured via rumen puncture during the adaptation to the finishing diets and throughout the finishing phase. Collection of rumen gasses occurred 5 hours after feed was offered. Hydrogen sulfide measurements were collected on day 0, 7, 14, 21, 28, 35, 49, 63, and 91; final finishing diets were provided on day 28. On day 0, steers began the dietary adaptation period which increased the concentrate portion of the diet to 85 percent over 28 days (Table 2). Adaptation diets increased the amount of concentrate (corn and DDGS) while reducing the amount of corn silage and alfalfa hay. Steers were then given a single 10 ml injection of penicillin to prevent infection after conclusion of the gas sampling procedure.
Table 2. Final finishing ration and adaptation diets (%, DM basis) fed to steers.
Diet Day
Stage of Adaptation Step 3 Step 4 14 21
Step 1 0
Step 2 7
Step 5 28
20% DDGS Alfalfa Hay Corn Silage DDGS1 Corn2 CSB3 Supplement4
20.0 40.0 -33.2 5.0 1.8
16.3 32.5 5.0 39.4 5.0 1.8
12.5 25.0 10.0 45.7 5.0 1.8
8.8 17.5 15.0 51.9 5.0 1.8
5.0 10.0 20.0 58.2 5.0 1.8
40% DDGS Alfalfa Hay Corn Silage DDGS1 Corn2 CSB3 Supplement4
20.0 40.0 -33.2 5.0 1.8
16.3 32.5 10.0 34.4 5.0 1.8
12.5 25.0 20.0 35.7 5.0 1.8
8.8 17.5 30.0 36.9 5.0 1.8
5.0 10.0 40.0 38.2 5.0 1.8
60% DDGS Alfalfa Hay 20.0 16.3 12.5 8.8 5.0 Corn Silage 40.0 32.5 25.0 17.5 10.0 DDGS1 -15.0 30.0 45.0 60.0 2 Corn 33.2 29.4 25.7 21.9 18.2 CSB3 5.0 5.0 5.0 5.0 5.0 Supplement4 1.8 1.8 1.8 1.8 1.8 1 DDGS = distillers dried grains plus solubles. 2 Corn fed either as dry-rolled corn or high-moisture corn. 3 CSB = concentrated separator byproduct. 4 Supplement contained (%, total ration DM basis): limestone 1.7%; vitamin A, D, and E premix 0.02% [Trouw Nutrition, Highland, IL (1,500,000 IU vitamin A, 500,000 IU vitamin D, and 500 IU vitamin E)]; Rumensin 0.02% (176 g/kg Monensin, Elanco Animal Health, Indianapolis, IN); Trace mineral premix 0.05% [Hubbard Feeds Inc., Mankato, MN (3.95% Ca, 2.56% Cu, 16.0% Zn, 4.0% Mn, 1,050 mg/kg I, and 250 mg/kg Co)]; 0.002% thiamin (analyzed concentration 13.55 mg/kg dietary DM). Two-day body weights were collected at arrival (day -28), beginning of dietary adaptation (day 0), beginning of the finishing phase (day 28), and the conclusion of the study. Intermediate weights were collected every 28 days as single-day weights to monitor animal performance (data not presented). Steers received a single implant containing 80 mg trenbolone acetate and 16 mg estradiol (Revalor-IS, Intervet Inc., Millsboro, DE) on day 28. Feed offered was recorded daily with feed refusals collected, weighed, and sampled weekly. Weekly feed samples were collected to determine dietary DM and nutrient composition. Average daily gain and G:F were calculated based on these data. Carcass characteristics were collected by trained personnel 24 hours after slaughter. Liver scores were recorded with evaluation based on procedures outlined by Brink et al. (1990).
Results The day × corn processing × DDGS concentration interaction for hydrogen sulfide gas concentrations was not significant (P = 0.91). Ruminal H2S concentration was affected by increasing DDGS concentration in the diet (P < 0.001) and day (P < 0.001), but not by corn processing method (P = 0.94). No differences in H2S concentration among treatments were observed on days 0, 7, 14, or 21 (P ≥ 0.14; Figure 1). On day 28, steers fed 60 percent DDGS had greater (P ≤ 0.006) H2S concentrations than those fed either 20 or 40 percent DDGS. Hydrogen sulfide concentration increased (P < 0.001) from day 28 to day 91 for steers fed 60 percent DDGS. Steers fed 60 percent DDGS had the greatest concentrations of H2S on day 91 (P ≤ 0.01). Hydrogen sulfide concentrations were either static (P = 0.68) or tended to decrease (P = 0.08) for steers fed 20 or 40 percent DDGS, respectively, from day 49 to day 91.
Figure 1. Change in hydrogen sulfide concentration (g/m3) caused by increasing dietary DDGS (DDGS) concentration in steers over adaptation from a medium-concentrate to high-concentrate finishing ration. Treatments were based concentrations of DDGS (20, 40, and 60% DM basis) as well as corn processing (high-moisture vs. dry-rolled corn). P values: corn processing (P = 0.94), DDGS (P < 0.001), and corn processing by DDGS (P = 0.36). Concentrations of hydrogen sulfide gas measured via rumenocentesis on hydrogen sulfide detector tubes (Gastec©, Kanawaga, Japan). Results for steer performance are reported in Table 3. There were no corn processing and DDGS concentration interactions (P ≥ 0.12). Furthermore, there was no effect of corn processing (P ≥ 0.14). Therefore the effects will be discussed as either linear or quadratic responses to increasing DDGS concentration. There were no differences in initial BW (P ≥ 0.82) due to DDGS inclusion with steers averaging 748 ± 26.4 pounds. Performance data was partitioned into adaptation (day 0 - 28) and finishing (day 29 - end). During the adaptation phase there were no differences in ADG, DMI, or G:F for DDGS concentration (P ≥ 0.35). During the finishing phase ADG and DMI decreased quadratically (P ≤ 0.02) while G:F decreased linearly (P = 0.01) with increasing concentration of DDGS in the diet. As a result of decreased ADG, final BW decreased linearly (P = 0.002) with increasing DDGS inclusion.
Table 3. Influence of corn processing and concentration of distillers dried grains plus solubles (DDGS) on animal performance of steers. Dry-rolled Corn High-moisture Corn 20% 40% 60% 20% 40% 60% 3 DDGS DDGS DDGS DDGS DDGS DDGS SEM
Item Initial BW, lb Final BW, lb Adaptation ADG, lb DMI, lb G:F Finishing
1,2
P value Corn
DDGS
L
Q
761 1372
750 1336
761 1289
750 1358
752 1396
750 1233
28.6 31.1
0.76 0.52
0.97 0.004
0.96 0.002
0.82 0.16
4.0 24.5 0.16
4.0 26.0 0.16
3.8 25.6 0.15
3.8 25.1 0.14
4.0 25.4 0.16
4.0 25.6 0.16
0.22 0.84 0.01
0.87 0.97 0.70
0.64 0.41 0.77
0.91 0.29 0.74
0.35 0.42 0.51
4.4 24.3 0.18
4.2 23.2 0.18
3.1 18.7 0.17
4.4 23.8 0.18
4.0 22.5 0.17
2.6 17.2 0.15
0.22 0.88 0.01
0.14 0.23 0.35
